Although the exact roles of LAG3 and sLAG3 in the CNS and PD are still unknown, based on the results of the study by Guo and colleagues, it has been speculated that LAG3 and sLAG3 imbalance in the brain may create an immunologically impaired microenvironment, susceptible to α-synuclein-mediated neurodegeneration, which the aggregated α-synuclein could utilize in order to spread in the CNS [40]. This evidence concerns the gene LAG3 and Parkinson disease.